1. Field of the Invention
This invention relates generally to cache storage of mobile digital content in a vehicular network and, more particularly, to a method and system of cache management in a vehicular network which computes a utility value for each piece of mobile digital content which a host vehicle encounters, uses the utility value to determine whether the piece of mobile digital content should be stored in the vehicle's cache, and periodically re-computes the utility value for all mobile digital content in the vehicle's cache to determine if any of the data should be evicted from the cache.
2. Discussion of the Related Art
Many modern vehicles include one or more wireless communication technologies, which can make the driving experience safer, more convenient, and more enjoyable for the driver and passengers of the vehicle. Among these, information and entertainment (or “infotainment”) systems have become particularly popular. Built-in cellular phone systems can provide internet access, in addition to their traditional voice communication capabilities. Many vehicles also commonly include other wireless communication technologies, such as satellite-based driver assistance systems, and Dedicated Short Range Communications (DSRC) or Wireless Local Area Network (Wi-Fi) systems. DSRC is often used for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) networks, both for infotainment purposes and otherwise.
In the infotainment world, there are many different types of digital content available for consumption. These include audio files containing music or other audio content, video files containing movies or other video content, information broadcasts (often known as podcasts), map and software updates for onboard systems, and others. While the variety and availability of digital content is great, it can be time-consuming and expensive to retrieve content which is of interest to a vehicle's occupants, because the particular piece of digital content is often only available from a source server via the internet, and the internet can only be accessed via cellular link. Meanwhile, because of the popularity of V2V communications, there is a huge amount of latent mobile storage space and high-speed communication bandwidth. However, much of the mobile storage space and high-speed vehicle-to-vehicle communication bandwidth are unused, because there is no established framework for cooperatively storing and sharing digital content between nodes in a V2V network.
There is a need for a cooperative cache management protocol which can be used in vehicle-to-vehicle networks. Such a protocol would enable a vehicle to collaborate with other neighboring vehicles for local retrieval of digital content of interest—and would increase the speed with which participants in the V2V network can obtain digital content, and reduce cellular internet access costs for participants in the V2V network.